Events & Promotions
|
|
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Nov 2007:30 AM PST
-08:30 AM PST
Learn what truly sets the UC Riverside MBA apart and how it helps in your professional growth
Nov 2211:00 AM IST
-01:00 PM IST
Do RC/MSR passages scare you? e-GMAT is conducting a masterclass to help you learn – Learn effective reading strategies Tackle difficult RC & MSR with confidence Excel in timed test environment- Nov 23
11:00 AM IST
-01:00 PM IST
Attend this free GMAT Algebra Webinar and learn how to master the most challenging Inequalities and Absolute Value problems with ease. 
Nov 2510:00 AM EST
-11:00 AM EST
Prefer video-based learning? The Target Test Prep OnDemand course is a one-of-a-kind video masterclass featuring 400 hours of lecture-style teaching by Scott Woodbury-Stewart, founder of Target Test Prep and one of the most accomplished GMAT instructors.
29 Apr 2005, 16:18
Kudos
Bookmarks
N
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
(N/A)
Question Stats:
0% (00:00) correct
0%
(00:00)
wrong
based on 0
sessions
History
Date
Time
Result
Not Attempted Yet
show workings;)
Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Data Sufficiency (DS) Forum
Still interested in this question? Check out the "Best Topics" block below for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
29 Apr 2005, 17:29
Kudos
Bookmarks
x^2 - y^2 = (x+y)(x-y)
(1) says x and y are even. Say x = 2p and y = 2q.
Thus
x^2 - y^2 = 2(p+q)2(p-q) = 4(p+q)(p-q)
Now if p and q are even, we get one more factor of two. Same if both are odd. However, if one is odd and one is even, then p+q and p-q are both odd.
Therefore insufficient.
(2). If x+y = 8p, we get
x^2 - y^2 = 8p(x-y) which is divisible by 8.
Sufficient.
(B).
(1) says x and y are even. Say x = 2p and y = 2q.
Thus
x^2 - y^2 = 2(p+q)2(p-q) = 4(p+q)(p-q)
Now if p and q are even, we get one more factor of two. Same if both are odd. However, if one is odd and one is even, then p+q and p-q are both odd.
Therefore insufficient.
(2). If x+y = 8p, we get
x^2 - y^2 = 8p(x-y) which is divisible by 8.
Sufficient.
(B).
30 Apr 2005, 01:40
Kudos
Bookmarks
C)...
1) x = 4 and y = 2 NO x = 6 y = 2 YES => both are even => insufficient
2) x-y <> x+y x = 8 and y = 0 YES x = 7 and y = 1 NO => insufficient
1)+2) when x and y are both even the result of (x+y)^2 or (x-y)^2 is a multiple of 8 or 0 => sufficient
1) x = 4 and y = 2 NO x = 6 y = 2 YES => both are even => insufficient
2) x-y <> x+y x = 8 and y = 0 YES x = 7 and y = 1 NO => insufficient
1)+2) when x and y are both even the result of (x+y)^2 or (x-y)^2 is a multiple of 8 or 0 => sufficient
